Shoe heel with exchangeable tread part



Jan. 24, 1967 K. H. NYLUND SHOE HEEL WITH EXCHANGEABLE TREAD PART Filed Aug. 27, 1965 INVENTOR. Knui Herberz Ng/und United States PatentO 3,299,542 SHOE HEEL WITH EXCHANGEABLE TREAD PART Knut Herbert Nylund, Box 77, Sundbyberg, Sweden Filed Aug. 27, 1965, Ser. No. 483,254 Claims priority, application Sweden, Oct. 9, 1964,

12,126/ 64 Claims. (Cl. 36-42) It has already been suggested to provide heels, especially on ladies shoes, with an exchangeable tread part which can be fastened to a sleeve-shaped and preferably metallic lower heel end portion that is rigidly interconnected or interconnectable with the rest of the heel and in which a stem protruding upwards from the tread part can be received. However, practical tests have proved that prior suggestions concerning the construction of such devices :are unsatisfactory from the one point of view or the other. The stresses on the heels frequently become very heavy,

particularly in the modern, very pointed heels of ladies shoes while at the same time the space available for housing an appropriate holding mechanism for the exchangeable tread part is highly limited.

This invention has for its object to provide an improved arrangement for holding a very easily exchangeable tread part which can be removed and replaced-also without the aid of a shoemaker if necessary. To meet reasonable practical demands the arrangement must be such that the tread part is retained very firmly and, especially, pre vented from turning relative to the rest of the heel, and furthermore-it must be possible to remove even a very Worn tread part without damagingthe mechanism. This invention offers a solution of this problem, which is both simple and-effective.

The main feature of the invention is that the stem of the exchangeable tread part has an unround, preferably square, crosssection and is adapted to be received in a matching cavity in-the lower end of a socket member,

.which is actuated by a spring and axially slidable in a hole in the heel end portion, the cavited lower end portion of said socket member beingaxially slotted and'having,

likewise, an unround, preferably square, cross section gradually increasing in size towards the tread part, and said hole in the heel end portion having a lower mouth matching said slotted socket end portion and tapering inwardly in such a manner that, when said spring is pulling said socket member inwardly in said hole, the stem of the tread part received in said socket cavity will be grasped and retained therein by wedge action.

Preferably the heel end portion is provided with a tubular extension extending upwardly through the rest of the heel and having an open upper end through which a suitable tool may be inserted to actuate the socket member in a downward direction against the action of the spring for the purpose of releasing the stem of the tread part, when replacement of said tread part is desirable.

Further features of the invention will appear from the following description of an embodiment thereof which has been illustrated in the accompanying drawing, wherein FIG. 1 shows a ladies shoe heel with an exchangeable tread part and an attachment therefor according to the invention,

FIG. 2 is an enlarged vertical section through the lower portion of the same ladies shoe heel accommodating the attachment mechanism for the tread part,

FIG. 3 is a cross section taken along the line IIIIII in FIG. 2,

FIG. 4 shows the heel end portion as viewed from below with the tread part removed, and

FIG. 5 is a top plan view of the tread part.

In FIG. 1 numeral 1 designates a ladies s'hoe heel made for instance of wood, plastic or the like and nor- 3,299,542 Patented Jan. 24, 1967 "ice the heel end portion 2 and the tubular extension 3 must,

of course, be firmly secured in the heel 1 in any suitable manner.

As will be more clearly apparent from FIGS. 2-5 the replaceable tread part 4, which is to be attached to the heel end portion '2 and which may be made of metal, plastic, leather or the like, is provided with a centrally protruding stem 5 of square or at all events unround cross. sectional shape. This stem 5 is adapted to be inserted in a corresponding square hole or cavity 6 in a socket member 7 moulded in plastic, preferably of the polyam-ide resin type such as the synthetic resin materials sold under the trade names nylon or Delrin. The lower cavited portion 7 of said socket member 7 is axially-slotted and has in its turn a square outer cross sectional contour (see particularly FIG. 4). Preferably one diagonally extending slot 8 only is provided in the lower portion of the socket member 7 in order to avoid atoo extensive weakening of the socket member but, if

desired and if the size and material of the socket so percross sectional dimensions of the square lower portion 7 of the socket 7 are gradually increasing in the downward direction while the upper portion of the socket -7 is cylin- "drical and has a threaded top end 7" on which a sleeve nut 9 with a slotted head 10 is screwed.

Between the head 10 of the sleeve nut 9 and the top end surface of the sleeve-shaped heel end portion 2 there is mounted a helical compression spring 11, which urges the socket 7 inwards and upwards through the heel end portion 2, the lower hole mouth 12 of which is adapted to fit the lower portion 7' of the socket 7 insofar that it is square in cross section and inwardly tapered. By this arrangement a sort of wedge action occurs between the socket 7 and the heel end portion 2 when the socket is pulled inwards, upwards by means of the spring 11, and this wedge action is utilized to make the lower portion 7 of the socket 7 grasp and retain the stem 5 of the tread part 4. Preferably, the dimensions of the lower portion 7' of the socket 7 and of the hole in the heel end portion 2 respectively are so selected and interrelated that the socket 7 cannot be pulled all through the heel end portion 2 by the spring even when no tread part stem 5 has been received in the central, square socket cavity 6. In this way the mechanismparts cannot be inadvertently separated and get lost, but on the other hand they can easily be removed intentionally by screwing the sleeve nut 9 off the top end 7" of the socket e.g. for replacement of a broken spring or the like.

A suitable selection of the taper of the lower portion 7' of the socket 7 will ensure a very reliable retention of the tread part stem 5 even with a moderately powerful spring 11, and since the tread part stem 5, the socket 7 and the hole of the heel end portion 2 are all of unround cross section, the tread part 4 is effectively prevented from turning relative to the heel end portion 2 and thus also relative to the heel 1 proper, with which the heel end portion 2 is connected. For removal of the tread part 4 a suitable tool for instance a pin 13 (FIG. 1), is inserted through the tubular extension 3, i.e. from the inside of the shoe, and utilized to press the sleeve nut 9 and thus also the socket 7 downwards and partly out of the heel end portion 2, whereby the grip on the wedged stem is released and the tread part 4 with its stem 5- can easily be replace-d. Separate replacement tread parts 4 (with related stems 5) should, of course, be available for the consumers in various materials, e.g. in metal for outdoor use and in plastic for in-door use, and it will be readily understood that very little technical skill is required to effect a change or replacement whenever desired. If the tread part 4 has been so extensively worn down that the heel end portion 2 has also become worn, the latter may in most cases be flattened and reconditioned by grinding, provided, of course, that the wear has not been permitted to go too far.

To ensure an improved engagement between the socket 7 and the stem 5 of the tread part 4, the stem may be provided with transverse corrugations or quite simply with a rough surface. The arrangement describe-d may be made in various sizes to suit various heel and shoe models. Also the length of the tubular extension 3 can, of course, be varied to suit various heel heights. If the heel 1 proper is made of a material having the sufiicient strength, the tubular extension 3 may, if desired, be dispensed with and replaced by a suitable bore through the heel proper. It is furthermore possible to choose any other cross sectional shape than the square one for the tread part stem 5 and the lower portion 7 of the socket 7, the essential thing being that these parts must be unround to prevent an unintentional turning of the tread part relative to the rest of the heel. Obviously this involves that it is even possible to use one unround cross sectional shape for the tread part stem 5 and another unround cross sectional shape for the outside of the tapered lower portion 7 of the socket 7. It should thus be understood that the invention is not confined to the embodiment shown in the drawing and described above, even if this particular form has been found very favourable also as far as the practical details are concerned.

I claim:

1. A shoe heel arrangement, particularly for ladies shoes, and of the type including an exchangeable tread part having an upwardly projecting stem of unround cross section and a sleeve-shaped lower heel end portion which is rigidly connected to the rest of the heel and in which said stem of the tread part is adapted to be received and retained, said arrangement comprising a spring-actuated socket member which is axially slidable within said sleeveshaped heel end portion and which in its lower end has a cavity adapted to receive and grip said unround stern of the exchangeable tread part, the cavited lower end portion of said socket member being axially slotted and having an unround outer cross section gradually increasing in size towards the tread part, and said heel end portion having a lower mouth matching said slotted socket end portion in cross section and tapering inwardly in such a manner that, when said spring is pulling said socket member inwardly in said hole, the stem of the tread part received in said socket cavity will be grasped and retained therein by wedge action.

2. A shoe heel arrangement according to claim 1, wherein said heel end portion is provided with a tubular extension extending upwardly through the rest of the heel and having an open upper end, through which a tool may be inserted to actuate said socket member in a downward direction against the action of said spring for the purpose of releasing the stem of the tread part.

3. A shoe heel arrangement according to claim 1, wherein said lower cavitied portion of the socket member has a square cross sectional contour and is slotted diagonally relative thereto.

4. A shoe heel arrangement according to claim 1, wherein a nut is removably attached to a threaded top end of said socket member and wherein said spring is mounted under compression between said nut and a shoulder on said heel end portion.

5. A shoe heel arrangement according to claim. 1, wherein said socket member is moulded of plastic, preferably a synthetic resin of the polyamide type.

References Cited by the Examiner UNITED STATES PATENTS 2,159,943 5/1939 Palley 36-38 2,263,186 11/ 1941 Parlchurst 3636- X 2,656,621 10/1953 Hoflman 36--42 2,875,532 3/1959 Fitzsirnrnons 3636 3,182,409 5/ 1965 Herremans 36--42 3,216,133 11/1965 Houle 36--36 X PATRICK D. LAWSON, Primary Examiner. 

1. A SHOE HEEL ARRANGEMENT, PARTICULARLY FOR LADIES'' SHOES, AND OF THE TYPE INCLUDING AN EXCHANGEABLE TREAD PART HAVING AN UPWARDLY PROJECTING STEM OF UNROUND CROSS SECTION AND A SLEEVE-SHAPED LOWER HEEL END PORTION WHICH IS RIGIDLY CONNECTED TO THE REST OF THE HEEL AND IN WHICH SAID STEM OF THE TREAD PART IS ADAPTED TO BE RECEIVED AND RETAINED, SAID ARRANGEMENT COMPRISING A SPRING-ACTUATED SOCKET MEMBER WHICH IS AXIALLY SLIDABLE WITHIN SAID SLEEVESHAPED HEEL END PORTION AND WHICH IN ITS LOWER END HAS A CAVITY ADAPTED TO RECEIVE AND GRIP SAID UNROUND STEM OF THE EXCHANGEABLE TREAD PART, THE CAVITED LOWER END PORTION OF SAID SOCKET MEMBER BEING AXIALLY SLOTTED AND HAVING AN UNROUND OUTER CROSS SECTION GRADUALLY INCREASING IN SIZE TOWARDS THE TREAD PART, AND SAID HEEL END PORTION HAVING A LOWER MOUTH MATCHING SAID SLOTTED SOCKET END PORTION IN CROSS SECTION AND TAPERING INWARDLY IN SUCH A MANNER THAT, WHEN SAID SPRING IS PULLING SAID SOCKET MEMBER INWARDLY IN SAID HOLE, THE STEM OF THE TREAD PART RECEIVED IN SAID SOCKET CAVITY WILL BE GRASPED AND RETAINED THEREIN BY WEDGE ACTION. 